Inspector Shane Ahmed of the South Wales Police is claiming that the episode Fair Cops? aired on 2 November 2003, was defamatory.

Presented by reporter Phil Parry, the programme alleged that South Wales Police were involved in fabricating evidence to protect their own officers, and focused in particular on the infamous Clydach murder case of 1999, in which local woman Mandy Power, her two young daughters and their grandmother were beaten to death.

It claimed police notes relating to an overheard conversation between David Morris – the man convicted in 2002 for the murders and jailed for life – and his solicitor, had been fabricated.

The episode, which won the 2004 Bafta Cymru award for current affairs said Ahmed, one of the investigating officers, wrote the conversation down on a series of Post-it notes.

Jeremy Clarke-Williams, a partner with Russell, Jones and Walker, the Police Federation’s solicitors representing Ahmed, told Press Gazette this week: “The allegations were extremely serious – about as serious as one can make against a police officer short of accusing them of murdering somebody.”

He added: “The allegation was that he fitted up a suspect in a murder case with the result that the suspect got convicted. If successful, I would expect Mr Ahmed to recover substantial damages.”

Clarke-Williams refused to be drawn on the size of Ahmed’s claim, but speculation has suggested he hopes to win damages of more than £150,000. Ahmed is also suing over the fact that BBC News Online contained a transcript of the programme, and other website postings, but these have since been removed. The BBC confirmed it had received the writ and said it will contest the claim.

Details of the dispute come as Panorama is facing an onslaught of angry responses – including the threat of another lawsuit and a formal complaint to BBC director general Mark Thompson – following the broadcast last week of an episode that alleged at least one International Olympic Committee member would accept cash for votes in relation to the UK’s bid for the 2012 games.

According to reports, Ivan Slavkov, the Bulgarian Olympic delegate suspended from the commission while it investigates allegations made in Buying The Games, has threatened to sue the BBC. A spokeswoman insisted it had not received any notice as we went to press.

British International Olympic Committee member Craig Reedie has written to complain amid concerns that the programme may have jeopardised the London bid. The BBC insisted it made clear that no representatives of the bid were involved.